Calculeaza respectand regula de la punctul b)

Rezolvare

a)
1087 - 7 x 7 = 1087 - 49 = 1038
230 - 7 x 8 = 230 - 56 = 174
140 - 7 x 8 = 140 - 56 = 84
780 - 8 x 2 = 780 - 16 = 764


b)
2733 + 5 x 9 = 2733 + 45 = 2778
513 + 9 x 8 = 513 + 72 = 585
200 + 7 x 9 = 200 + 63 = 263
403 + 8 x 2 = 403 + 16 = 419

c)
9 x 9 - 7 x 6 = 81 - 42 = 39
9 x 8 + 5 x 6 = 72 + 30 = 102
6 x 8 - 3 x 9 = 48 - 27 = 21
4 x 2 + 3 x 6 = 8 + 18 = 26